Laboratory Tests Using Chlorine Trifluoride in Support of .../67531/metadc...regarding the use of chlorine trifluoride (ClF3) for removal of uranium-bearing deposits in the Molten

ORNL/TM-13403

Laboratory Tests Using Chlorine Trifluoride in Support of Deposit Removal at MSRE

D. F. Williams J. C. Rudolph G. D. Del z ’ - - e ’ * * s. L. Log e=. 7 - / ” -

D. W. Simm L. M. Toth 2 2 13

This report has been reproduced directly from the best available copy.

Available to DOE and DOE contractors from the Office of Scientific and Technical Information, P. 0. Box 62, Oak Ridge, TN 3783 I ; prices available from (423) 576-840 1, FTS 626-840 1.

Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, VA 221 6 1.

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied. or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark. manufacturer, or otherwise. does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government of anv agency thereof.

DISCLAIMER

Portions of this document may be illegible electronic image products. Images are produced from the best available original document.

*

r

OR.NL/TM- 13403

Chemical Technology Division

LABORATORY TESTS USING CHLORINE TRIFLUoR.DE IN SUPPORT OF DEPOSIT REMOVAL AT MSRE

D. F. Williams J. C. Rudolph G. D. Del CUI

D. W. Simmons L. M. Toth

s. L. Loghry

Datepublished - April 1997

Prepared by the OAK RIDGE NATIONAL LABORATORY

Oak Ridge, Tennessee 37831-6285 managed by

LOCKHEED MARTIN ENERGY RESEARCH COW. for the

U.S. DEPARTMENT OF ENERGY under contract DE-AC05-960R22464

http://TRIFLUoR.DE

CONTENTS

LIST OF TABLES ............................................................................................................ v LIST OF FIGURES ........................................................................................................ ~i

EXECUTIVE SUMMARY ............................................................................................... ix ABSTRACT ...................................................................................................................... 1 1 . INTRODUCTION ....................................................................................................... 1 2 . EXPERIMENTAL ....................................................................................................... 3

2.1 TRAPPING OF CIF3 ................................................................................... 3

..

2.1.1 Materials and Equipment ................................................................ 3 2.1.2 Test Method .................................................................................... 4

2.2 EXPOSURE OF IRRADIATED SALT TO ClF3 ......................................... 6 2.2.1 Materials and Equipment ................................................................ 6 2.2.2 Test Method .................................................................................... 6

3 RESULTS 7 3.1 TRAPPING RESULTS .................................................................................. 7

REFERENCES ................................................................................................................ 19

. .................................................................................................................... 3.2 RESULTS FROM EXPOSURE OF IRRADIATED SALT TO ClF3 .......... 16

Appendix A . COMPLETE FTIR RESULTS ................................................................. 21 Appendix B . EXTINCTION COEFFICIENTS USED IN THIS STUDY .................... 37

... 111

LIST OF TABLES

Table

1 2 3

Materials and equipment used in CIF, trapping tests ........................................... 3 Summary of fmed-bed trapping parameters and performance .............................. 7 Estimated amount of gases recovered from evacuation of molecular sieve after the low-flow trial .............................................................. 16

V

LIST OF FIGURES

Figure

10

11

12

13

Page

Diagram of the experimental system for fixed-bed trapping ................................ 5 Wall temperatures and flows during high-flow trial ............................................. 8 Wall temperatures and flows during low-flow trial .............................................. 8 Representative C103F infrared spectrum ............................................................. 9 Representative C102 infrared spectrum ............................................................. 10 Representative C102F infrared spectrum ............................................................. 10 Evolution of halogen oxide infrared peaks during high-flow trial ...................... 12 Evolution of halogen oxide infrared peaks during low-flow trial ....................... 13 Gas concentrations measured downstream of the alumina trap during high-flow trial .......................................................................................... 14 Gas concentrations measured downstream of the alumina trap

Halogen oxide gases recovered from evacuation of molecular sieve after low-flow trial .............................................................................................. 15 Infrared spectra from ClF3 passivation and from exposure of irradiated salt to ClF3 ........................................................................................... 17 Infrared spectra from ClF3 passivation and from exposure of irradiated salt to ClF3: 625-cm-l region .............................................................. 18

during low-flow trial ........................................................................................... 14

vii

EXECUTIVE SUMMARY

This investigation complements a previous Chemical Technology Division study (ORNL/TM-13191) on treatment of the reactive gases present in the Molten Salt Reactor Experiment (MSRE) off-gas system. This work addresses the perfomance of the Reactive Gas Removal System trapping materials with chlorine trifluoride (ClF3) and the potential for generating halogen oxides in the off-gas. The basic performance of the alumina/molecular sieve system with ClF3 is essentially equivalent to that seen during fluorine trapping operations. Temperatures and fluorine loadings are not significantly different fiom those seen during tests with F2. For operations with significant levels of CW3 (such that a hot reaction front is established), a very small amount of chlorine dioxide (C102) escapes the alumina column during a short period of time. Only upon breakthrough of the alumina column are significant levels of halogen oxides detected. At low CF3 flows (those that do not establish a hot reaction front), perchloryl fluoride (C103F) is generated during much of the trapping operation and, as before, a very small amount of CIO, is detected for a short period. Breakthrough is again accompanied by significant generation of halogen oxides. The only significant product seen before breakthrough is C103F - a rather unreactive and i~ocuous gas.

Only a limited amount of information was obtained about the retention of gases on the trapping media. It appears that the capacity and affmity of the molecular sieve are such that very little halogen oxide will be seen in the effluent from the second column during nonnal operation. No halogen oxides were detected after the low-flow trial during extensive purging of both columns with helium. Upon evacuation of the molecular sieve column and cold trapping of the exhaust, low levels of halogen oxides were recovered (< 20 std cc). Evacuation and cold trapping of the alumina column were inconclusive, but we expect a low level of sorption on the spent alumina. Furthermore, this level should diminish with an increasing temperature in the alumina reaction front.

After treatment of irradiated MSRE simulant salt with 0.5 atm of ClF3 for 18 h, temperature and weight measurements, plenum gas infrared spectra, and visual inspection all indicated that the salt is basically inert to this level of ClF3 exposure.

ix

LABOMTORY TESTS USING CHLORINE TRIFLUOFUDE IN SUPPORT OF DEPOSIT REMOVAL AT MSRE

D. F. Williams, J. Rudolph, G. D. Del Cul, S. L. Loghry, D. W. I

ABSTRACT

immons, and L. M. Toth

Experimental trials were conducted to investigate some unresolved issues regarding the use of chlorine trifluoride (ClF3) for removal of uranium-bearing deposits in the Molten Salt Reactor Experiment (MSRE) off-gas system. The safety and effectiveness of operation of the fixed-bed trapping system for removal of reactive gases were the primary focus. The chief uncertainty concerns the fate of chlorine in the system and the potential for forming explosive chlorine oxides (primarily chlorine dioxide) in the trapping operation. Tests at the MSRE Reactive Gas Removal System reference conditions and at conditions of low ClF3 flow showed that only very minor quantities of reactive halogen oxides were produced before column breakthrough. Somewhat larger quantities accompanied breakthrough. A separate test that exposed irradiated MSRE simulant salt to ClF3 confmed ow expectation that the salt is basically inert for brief exposures to ClF, at room temperature.

1. INTRODUCTION

This work is motivated by the need to ensure safe and effective use of chlorine trifluoride (ClF3) as a fluorinating agent for removal of uranium-bearing deposits in the Molten Salt Reactor Experiment (MSRE) off-gas system. The need to use a powerf'ul fluorinating agent, such as ClF3, for deposit removal was demonstrated by the inability to remove the existing MSRE off-gas deposits by vacuum sublimation. It was concluded that the uranium-bearing plugs could not be pure u F 6 . Instead, they probably contained hydrolyzed material (e.g., hydrous U02F2 ) that resulted from moisture intrusion or reduced uranium fluorides (e.g., uF@F5) that resulted from the self-induced radiolysis of u F 6 deposits.

The primary focus for this laboratory testing is the disposal of excess CIF, in the existing two-stage alumina/molecular sieve fixed-bed traps. Previous studies [ I ] have shown that alumina is an effective trapping agent for the fluorine content of C1F3 but that most of the chlorine passes through this trap. Although a number of studies have investigated the reaction of ClF3 with various materials, none of them provide a basis for predicting the outcome in the alumina bed [ 2 4 ] . Reaction of ClF3 with oxide surfaces

1

can produce many different halogen oxides depending upon the temperature, moisture level, residence time, CF3 concentration, and specific reactivity of the solid. The behavior in a fixed-bed column is further complicated by sorption effects in the downstream packing. The complicated decomposition mechanism of one of the halogen oxides, chlorine dioxide (C102), adds yet another variable to be accounted for /7]. Because of these uncertainties and the fact that the potential exists to produce explosive halogen oxides (e.g., C102), this brief experimental test program was initiated. Some of the same reaction products that occur in the alumina trap will occur in the MSRE off-gas piping to a much lesser (and indeterminate) extent. However, OUT focus on the trapping operation is appropriate because it has by far the greatest potential for generation of explosive gases.

2

2. EXPERIMENTAL

.

2.1 TRAPPING OF CIF,

2.1.1 Materials and Equipment

Materials

The trapping materials used for this work, listed in Table 1, are identical to those used in a previous study (81 and are those presently in use in the MSRE Reactive Gas Removal System (RGRS). For the high-flow trial, full columns of alumina (48.1 g of Al2O3) and molecular sieve (42.5 g of 13X pellets) were used. For the low-flow trial , only a one-third charge of packing was used (16.0 g of A1203, 14.2 g of molecular sieve). The compressed gases used for these tests were ultra-high-purity helium (Air Liquide America Corp.) and research-grade CIF3 (Air Products and Chemicals, Inc.). Neither feed gas had significant levels of infi-ared-active impurities. Potassium hydroxide (1 M> was used for the final scrubbing of the exhaust gas.

Table 1. Materials and equipment used in CIF, trapping tests Item Description

Materials" Alumina Molecular sieve

LaRoche Chemicals A-201 5 x 8 mesh, spherical Linde 13X, 1/8-in.-diam cylindrical pellets

Equipmentb* Alumina column Molecular sieve column CLF, flow controller

0.75-in.-OD x 0.035-in.-wall304L SS tube, 1 ft long 0.75-in.-OD x 0.035-in.-wall304L SS tube, 1 ft long Tylan 2900M mass-flow controller,

100 sccm F2 (full scale) He flow controller

FITR flow cell FIlR instrument

Temperature and flows Data loggingb

MKS mass-flow controller type 1459C01667185,

10-cm path, 39-mm-ID ZnSe windows Bomem MB-104 with ZnSe internal optics

lo00 sccm N2 (full scale)

Automatic with Validyne UPC601-T card and Easy Sense v2.01 DOS program on IBM-386 PC

FTIR spectra

"Same materials and preparation used in previous tests and now being used at the

Manually every 5 min using WinBomemEasy software on IBM-486 PC

Molten Salt Reactor Experiment. FI'IR = Fourier transform infrared. sccm = standard cubic centimeters per minute.

3

Equipment

The experimental equipment consisted of auxiliary piping, vessels, and instruments integrated with an existing reactive-gas manifold. This system is depicted in Fig. 1, and the significant equipment items are identified in Table 1. All of the piping in the system is monel tubing, except for the 304L SS fixed-bed columns. Much of the manifold was not necessary for the actual flow test; however, it was essential for preparation of the system, troubleshooting during operation, and disposaVanalysis of excess reactive gases.

Not shown in Fig. 1 are the thermocouples used to monitor the wall temperatures of the alumina and molecular sieve columns. For the alumina column, wall temperatures were measured at the entrance, middle, and exit of the column. Only the wall temperature at the entrance to the molecular sieve column was measured. In order to obtain representative wall temperatures, l/l&in.-diam Type K thermocouples were firmly clamped to the column wall and then insulated in the vicinity of the tip of the thermocouple. For the high-flow trial, the entrance and exit thermocouples were located 1 in. from the ends of the bed, for the low-flow trial, they were located as close as possible to the actual bed entrance and exit. The middle thermocouple was always located equidistant from the ends of the bed. Another minor feature not shown in Fig. 1 is the heat tracing of piping between the two columns. A 1-ft section of monel tubing (6-in. length of 1/4-in. tubing followed by 6-in. length of 1/2-in. tubing) connecting the two columns was heated to 100°C in order to approximate the gas residence time in the heat-traced line that exists in the RGRS.

2.1.2 Test Method

Use of a scaleddown fixed bed operated at the reference superficial velocity of feed constituents to predict full-scale performance is a widely accepted practice and was successfully used in a previous study of fluorine trapping 181. The beginning of a trial was established by introduction of ClF3 to a flowing helium stream. Both columns were operated upflow, as shown in Fig. 1, but the flow bypassed the molecular sieve column during periods when the alumina exhaust was ported to the Fourier transform infrared (FT’IR) spectroscopy flow cell. This limitation was not significant, and all of our

4

7

A

.- VI (b * Q 0 0

3 I * *

I I

1

E

1 -3-

i oil crc .I

5

experimental goals were met with this manner of operation. Because we had only one FTIR instrument, choices had to be made about which column’s exhaust gases would be monitored during a particular period of the trial. In general, we adopted the approach of monitoring the exhaust from the alumina column until an infrared-active species appeared and established a semblance of steady behavior. During the second trial at low ClF3 flows, we intentionally ported more gas to the molecular sieve column to assess the ability of the second column to load and retain halogen oxides. Reference spectra on an evacuated or helium-filled cell were taken at the beginning and end of each trial. All spectra were taken with a 4504400 cm-1 wavenumber range (1-cm-1 resolution), and five averaged scans were taken at a rate of six scans/minute for each measurement. For both trials there were no significant flow restrictions and the system pressure was just slightly above atmospheric pressure due to the hydrostatic pressure (-0.9 psi) associated with the caustic scrubbers.

2.2 EXPOSURE OF IRRADIATED SALT TO CIF3

2.2.1 Materials and Equipment

The materials and equipment for this batch exposure test consisted of a 1/2-in.-OD x 0.035-in.-wall x 4-in.-long monel tube capsule connected to the existing manifold/FlTR setup shown in Fig. 1. The open end of the capsule was sealed by compression fittings and an all-metal valve (monel internals). This assembly, along with the manifold and optical cell, was preconditioned with 0.5 atm of ClF3 to passivate all surfaces. The capsule was pumped out to high vacuum, backfilled with helium, and transferred to an inert-gas glove box for loading with irradiated MSRE simulant salt. In the glove box 0.98 g of powdered MSR-2 simulant salt (-2% fluorine deficient, final High Flux Isotope Reactor cooling pool discharge on July 19, 1996) was loaded into the open capsule, the capsule was reassembled, and the contents were isolated by closing the attached valve. After connecting the capsule to the manifold, a thermocouple was clamped to the bottom of the tube and the entire capsule was insulated with a 3-in.-thick layer of fiberglass insulation.

2.2.2 Test Method

Part of the test involved measuring the infrared bands that we would expect to see in the absence of salt exposure, that is, those features associated with the reaction of ClF3 with the piping and equipment (“passivation”) . Representative “passivation” spectra were obtained in the course of preconditioning the system and during charging of the capsule with CE3. The same FTIR instrumental parameters used during the trapping trials were used for this test.

6

3. RESULTS

3.1 TRAPPING RESULTS

The results consist of measurements of the wall temperatures, i n b e d spectra, and breakthrough behavior during the trapping of ClF3 on the scaled-down packed beds assembled for this study. Two trials were conducted with the same total superficial gas velocity (vmM = 40 cdmin), but one trial was conducted with a high ClF3 flow and the other had a low ClF3 flow. The trial at high ClF3 flow (49% ClF3 / 5 1% He) was similar in character to the RGRS trap limit of lo00 sccm of F2 established in a previous study [8]. The second trial, at low ClF3 flow, used a 5% ClF3 / 95% He mixture. The major results from these two tests are summarized in Table 2, and the detailed temperature and flow profdes are displayed in Figs. 2 and 3. The erratic pattern of the temperature measured at the alumina bed exit during the high-flow trial was due to a thermocouple failure. The exit temperature profile should resemble a reflection of the entrance profile, as was seen in previous work [8].

Table 2. Summary of fixed-bed trapping parameters and performance

Bed clF3 CF3 Peak wall [C1021 F loading at length flow Heflow molarflux temp detected breakthrough

Peak

(in.) (sccm) (sccm) (rnoVm2-s) ("C) (ton)' (g F/ g Al203)

12 48. 50 0.15 210 2.3 0.48

4 4.8 95 0.015 40 13.4 0.135

"Based upon a provisional conservative estimate of the peak extinction associated with the low- resolution measurement of the 1109-cm-' band of 300 torr-cm per absorbance unit. See Appendix B.

The temperatures and fluorine loading established in the high-flow trial are quite close to the values found in previous studies with fluorine [ I , 81 and ClF3 [ I ] . The lower temperature and decreased loading of fluorine on alumina for the low-flow trial were expected and were also found in previous studies for conditions which did not establish a hot reaction front [I] . It is interesting to note that the heating of the molecular sieve by reaction with ClF3 is similar in magnitude to that seen with alumina.

7

G e I Y

E s E

He

Fig. 2. Wall temperatures and flows during high-flow trial.

45 95 sccm H- +

95 sccm He, 4.8 sccm CIF,

aluminabedentrance 40 ,e-, r'r' alumina bed midpoint

c ,) 8

- \ alumina bed exit - - - - - s a I d \ - - - - - - - - - molecular sieve bed entrance \ 1 35 1 At." - \ I 8

30

25

20 0 1 2 3 4 5

Elapsed Time (h)

Fig. 3. Wall temperatures and flows during low-flow trial.

8

In this section only a summary of the infrared (FTIR) spectroscopy results is presented - a complete display of the spectra is included in Appendix A. The most important F"IR results concern the generation of halogen oxide gases during trapping of ClF3 on alumina. In Figs. 4-6, representative spectra of the predominant halogen oxide species (C102, C102F, CIO,F ) are displayed. These spectra reveal that there are ample features to establish the identity and concentration of each halogen oxide without resorting to extensive deconvolution. The only potential complication, the overlap of the 1109-cm-1 C102 band and the 1106-cm-1 CI02F band, did not present itself because these species did not appear together. This is likely to be the case in systems such as this one that have either a deficiency or an overabundance of fluorinating agent, since C102 is rapidly converted to C102F by fluorine or CF3 191. Nominal concentrations were calculated from estimates (see Appendix B) of the extinction coefficients of these bands.

0.8

0.6

0.4

0.2

0

I I

% m

1400 1300 1200 1100 1000 900 800 7 0 0 6 0 0

Wavenumber (cm- '1

Fig. 4. Representative C103F infrared spectrum (spectrum no. 11 from low-flow trial).

9

0.06

0.02

0

2000 1500 1000

Wavenumber (cm- ')

Fig, 5. Representative C102 infrared spectrum (spectrum no. 18 from high-flow trial),

- 0.7 1

L

0 . 6 :

0 . 5 -

0 . 1 7

s

1400 1300 1200 1100 1000 900 800

Wavenumber (cm- ') 700 600

Fig. 6. Representative CIOzF infrared spectrum (spectrum no. 25 from high-flow trial). Note: minor level of C103F is also present.

10

The evolution of infrared-active species in the exhaust gas from the alumina column is shown in Figs. 7 and 8. In these figures each ordinate in the stack of spectra is independently scaled to show maximum detail (i.e., peak heights should not be compared across the stack). The quantitative results associated with these features are summarized in Figs. 9 and 10. For the high-flow, trial a small amount of C102 (- 2 torr) was detected in the exhaust from the alumina column 40 min prior to column breakthrough. This gas could have been present only for a short period of time (< 17 min). The measured C102 level was somewhat higher during the low-flow mal (- 15 torr) and occurred about 90 min prior to column breakthrough. As in the previous trial, the gas was present for only a very short period of time (- 14 min). For both trials an increasing level of halogen oxides (primarily C103F and C102F) and HF accompanied the ClF3 breakthrough of the alumina bed. For the high-flow trial this increase is with respect to an infrared-transparent exhaust gas (i.e., no halogen oxides), while for the low-flow trial this increase is superimposed upon a relatively constant generation of C103F.

The FTIR results discussed previously and displayed in Figs. 9 and 10 all refer to detection directly downstream from the alumina column. No infrared-active species were seen in the exhaust gas from the molecular sieve column during the low-flow trial, even after extensive purging with helium. After the low-flow trial, small amounts of halogen oxides (< 20 std cc) were recovered from the molecular sieve by pumping down the column to high vacuum and cold trapping the exhaust. The spectrum from expansion of the cold trap contents (after warming to room temperature) is shown in Fig. 11, and estimates of the amount of recovered gases are summarized in Table 3. In addition to the species identified in Table 3, SiF4, CO,, and very small amounts of gas with absorption bands at 849,887,1270, and 1504 cm-1 are present in the recovered sample. These "unidentified" peaks are all consistent with the reported spectrum of S02F2 191. The source of sulfur in the system is not known. Recovery of material sorbed on the alumina column after the low-flow trial was also attempted, but the results were inconclusive because of leakage of ClF3 into this sample from the supply piping.

These results indicate that the basic performance (i.e., loadings, temperatures) of the alumina bed with CLF3 is very similar to that with fluorine. The major difference between the two - the potential for generation of halogen oxide gases with ClF3 - is virtually a nonissue for standard operation with flows of ClF3 that establish a hot reaction front. A very minor amount of C102 was detected for only a short period of time. The only other generation of halogen oxide gases was associated with column breakthrough. For the case of a cold reaction front (i.e., low ClF3/F2 flows), more halogen oxides are form&, however, the dominant species is perchloryl fluoride (C103F), a relatively stable compound.

11

T = 3.08 I I I

IO 1400 1200 I000 800

W avenumber (cm- l)

Fig. 7. Evolution of halogen oxide infrared peaks during high-flow trial.

m s 0

II H

i i 0

II t-c

2

M S L 3 Q

.I

B L Q

rr 0

13

alumina exhaust '0°:1 I I I I I I I I I I I I I I I l l I I I I I I sampling 171 I I I I I111 "<*

4 molccularsieve

20

15

A

- - I I I I Ill I I 1 1 1 1 1 1 1 I I I I I l l I I I I i - - - -

3.5 0 0 .5 1 1.5 2 2.5

Elapsed Time (h)

3 4

Fig. 9. Gas concentrations measured downstream of the alumina trap during high-flow trial.

_ I

I H

0 I I u t I 1 I I I I L 7 1 I I I V I I I I I t I I

0 1 2 3 4

Elapsed Time (h)

nma exhaust sampling

molecular sieve exhaust sampling

Fig. 10. Gas concentrations measured downstream of the alumina trap during low-flow trial.

14

I

a

V

I I I (b. I I 1 a, 4 i I

P k .- t

(Y

15

Table 3. Estimated amount of gases recovered from evacuation of molecular sieve after the low-flow trial

Final expanded volume: - 600 cc Estimated amount

Component Wavenumber (cm-1) Peak absorbance (std cc)

C103F c102

716 1109

0.88 0.48

3.1 1 1.4'

C102F 1272 0.20 1.4

Total 15.9 'Based upon a provisional conservative estimate of the peak extinction associated with the low-

resolution measurement of the 11 09-cm-' band of 300 torr-cm per absorbance unit. See Appendix B.

3.2 RESULTS FROM EXPOSURE OF IRRADIATED SALT TO CIF,

After pumping down the salt sample to a high vacuum, 0.5 atm of CF3 was admitted to the capsule and optical cell, and the system was then isolated by valves. No rise in outer-wall temperature was detected at the bottom of the capsule. The exposure of the salt was continued for 18 h before the first gas sample was expanded from the capsule to the optical cell (from -10 cc to -120 cc, or an expansion factor of 13). Comparison of the passivation spectrum with the sample gas spectrum in Fig. 12 reveals that all features present in the gas sample are also present in the passivation gas. In Fig. 13 a more detailed look at the region near the strongest UF6 absorption band (625 cm-l) shows that only the 630-cm-l bands of C19F are present in this region. No change in sample weight was measured after capsule evacuation, helium backfill, and unloading in the inert glove box.

16

1

-47 --I_-

/

r

r I I I I I I 1 I I 1 I a In * m e4 c- 0

4

17

0 8

0 0 I-

O 0 00

0 0 Q,

0 0 0 T-

O 0 T- T-

7 E

0 0 m r

0 0 =r

0 0 UY T-

0

Q m

Y Y -

E & 0

c

18

REFERENCES

1. Otey, M. G., and Bayne, C. K., Fixed Bed Trapping for Gaseous Fluoride Efluent Control, KY-705, Paducah Gaseous Diffusion Plant (June 1980).

2. Farrar, R. L., Safe Handling of Chlorine Trijluoride and the Chemistry of Chlorine Oxides and Oxyfluorides, K-1416, Oak Ridge Gaseous Diffusion Plant (November 1960).

3. Farrar, R L., and Barber, E. J., Some Considerations in the Handling of Fluorine and Chlorine Fluorides, WET-252, Oak Ridge Gaseous Diffusion Plant (July 1979).

4. Shrewsberry, R. C., and Williamson, E. L., “Chemistry of the Chlorine Trifluoride - Uranyl Fluoride Reaction,” J. Znorg. N u l . Chem. 28,2535-39 (1966).

5. Cooper, T. D., et al., “Evidence for ClOF as the Primary Product of the Reaction of ClF3 with H20,” J. Inorg. Nucl. Chem. 34,3564-67 (1972).

6. Ellis, J. F., and Forrest, C. W., “Some Studies in the Inorganic Chemistry of the Reaction Between Uranyl Fluoride and Chlorine Trifluoride,” J. Inorg. Nucl. Chem. 16, 150-153 (1960).

7. McHale, E. T., and von Elbe, G., “The Explosive Decomposition of Chlorine Dioxide,” J. Phys. Chem. 72, 1849-56 (1968).

Rudolph, J. C., et al., Laboratory Tests in Support of MSRE Reactive Gas Removal, ORNL/TM-13191, Oak Ridge National Laboratory (in press).

8.

9. Lide, D. R., et al., “The Vibrational Assignment of Sulfuryl Fluoride,” Spectrochim. Acta 21,497-501 (1965).

19

Appendix A

COMPLETE FTIR RESULTS

I -

~- I ,

Table A. 1 and Figs. A.l-A.10 provide complete documentation of the FTIR results from this study. Because of minor deposition on and degradation of the ZnSe optical windows (evident as rounded “window bands”) and slight variations in the moisture and C02 levels in the optical path, some of the spectra are referenced (by spectral subtraction) to a featureless spectrum taken during the actual trial rather than to the initial reference spectrum. This subtraction is indicated in the following table, and the subtrahend spectrum is available for inspection in the graphs. This normalization greatly improves the clarity of the results. Note also that the growth and decay of absorbance bands are influenced by the dilution and backmixing introduced by the piping and infrared cell volume. These downstream volumes broaden the concentration history of the species that escape the alumina column. This effect is especially evident when the flow path is switched from analysis of one column’s exhaust to the other.

Special comments need to be made about the spectra after breakthrough of the alumina column during the high-flow trial (nos. 28-39). The features in these spectra are primarily from SiF, (1030-~m-~ line) and Clog. Silicon tetrafluoride is an expected product from reaction of the molecular sieve (an aluminosilicate) with ClF3, and C103F is one of the other predominant reaction products at low temperatures. However, the fact that these species are seen in the exhaust gas of the high-flow trial but not of the low-flow trial needs some explanation. The molecular sieve used for the high-flow trial had seen some slight use in a previous trial with ClF3 and may have had some sorbed species on the packing near the exit. The molecular sieve used in the low-flow trial had not seen previous exposure to ClF3 or exhaust gases. The molecular sieve from both trials experienced about 0.4 h of feed flow after the breakthrough of the alumina column. Therefore, the molecular sieve charge from the high-flow trial reacted with ten times the amount of ClF3 seen by the molecular sieve of the low-flow trial. This more extensive reaction accounts for the species detected in the exhaust gas during the high-flow trial. In any event, the exhaust species seen in spectra nos. 28-49 of the high-flow trial are due to reaction of the molecular sieve with ClF3 after breakthrough of the dumina column. If the alumina column is not operated past breakthrough, we expect to see very few infrared-active species in the exhaust gas of the molecular sieve column.

23

Table A.l. Identification of F I l R spectra Spectnun no. Elapsed time (h) Sampling detail@

High-flow trapping 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

32

33 34 35 36 37 38 39

0.00 0.08 0.22 0.27 0.28 0.32 0.37 0.40 0.55 0.72 0.87 1.05 1-32 1.57 1.77 2.02 2.17 2.37 2.45 2.50 2.67 2.77 2.85 2.92 2.97 3.08 3.13 3.20 3.25 3.30 3.37

3.45

3.50 3.57 3.62 3.65 3.68 3.75 3.78

Alumina effluent, started ClF3 flow Alumina effluent Alumina effluent Alumina effluent Alumina effluent Alumina effluent Alumina effluent Alumina effluent Alumina effluent Alumina effluent Alumina effluent Alumina effluent Alumina effluent Alumina effluent Alumina effluent Alumina effluent Alumina effluent (- no. 16) Alumina effluent (- no. 17) Alumina effluent (- no. 17) Alumina effluent (- no. 17) Alumina effluent (- no. 17) Alumina effluent (- no. 21) Alumina effluent (- no. 21) Alumina effluent (- no. 21) Alumina effluent (- no. 21) Molecular sieve effluent (- no. 21) Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent, stopped CE3, increased to 500 sccm He Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent

24

Table A.l (continued) Spectrum no. Elapsed time (h) Sampling &tailsa

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

0.00 0.05 0.12 0.18 0.28 0.43 0.50 0.53 0.58 0.65 0.70 0.73 0.85 0.92 1 .oo 1.03 1.07 1.12 1.28 1.45 1.50 1.55 1.60 1.63 1.68 1.73 1.82 1.87 1.90 2.00 2.05 2.10 2.15 2.20 2.32 2.42 2.57 2.73 2.83 2.90 2.97 3-02 3.08

Low-flow trapping Alumina effluent, started ClF3 flow Alumina effluent Alumina effluent Alumina effluent Alumina effluent Alumina effluent Alumina effluent Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent Alumina effluent (- no. 11) Alumina effluent (- no. 11) Alumina effluent (- no. 11) Alumina effluent (- no. 11) Molecular sieve effluent (- no. 11) Molecular sieve effluent (- no. 11) Molecular sieve effluent (- no. 11) Molecular sieve effluent Molecular sieve effluent (- no. 19) Alumina effluent (- no. 20) Alumina effluent (- no. 20) Alumina effluent (- no. 20) Alumina effluent (- no. 20) Alumina effluent (- no. 20) Alumina effluent (- no. 20) Molecular sieve effluent (- no. 20) Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent Alumina effluent (- no. 30) Molecular sieve effluent (- no. 30) Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent Molecular sieve effluent (- no. 37) Alumina effluent (- no. 38) Alumina effluent (- no. 38) Molecular sieve effluent (- no. 38) Molecular sieve effluent Molecular sieve effluent

25

Table A.l (continued) Spectrum no. Elapsed time (h) Sampling detail8

Molecular sieve effluent, stopped CF3, maintained 95 sccm He 3.27 44

45 3.48 Molecular sieve effluent 46 3.63 Molecular sieve effluent 47 3.80 Molecular sieve effluent 48 4.17 Molecular sieve effluent 49 4.55 Molecular sieve effluent

uSpectral subtraction is indicated in parentheses.

26

.

5

4

3

2

0 4

no. 1: 0.00 h, alumina effluent, started ClF3 flow

no. 2 0.08 h, alumina effluent


no. 4: 0.27 h, alumina effluent

no. 5: 0.28 h, alumina effluent - L

no. 6: 0.32.h, alumina effluent




no. 10: 0.72 h, alumina effluent , I I I I I I I I I I I I 1 1 I 1 I 7

4Mx) 1600 3200 2800 2400 2000 1600 1200 800

Wavenumber (cm-1)

Fig. A.l. Spectra from high-flow trapping, nos. 1-10 (elapsed time from 0 to 0.72 h).

27

I

.e

.6

A

2

0

1:

Fig. A.2. Spectra from high-flow trapping, nos. 11-20 (elapsed time from 0.87 to 2.5 h).

28



no. 13: 1.32 h, alumina effluent . no. 14 1.57 h, alumina effluent -

no. 15: 1.77 h, alumina effluent -, . .

no. 16 2.02 h, alumina effluent - . . +

no. 17: 217h, alumina effluent (-no. 16)

no. 18: 2.37 h, alumina effluent (- no. 17)

no. 1 9 2.45 h, alumina effluent (- no. 17)

I I I I i I I I I I I I i I I I i I 1400 I300 I200 I100 loo0 900 800 700 600

Wavenumber (cm-')

A

2

C

1

no. 21: 2.67 h, alumina effluent (-no. 17)


rcI


RO. 24: 2.92 h, alumina effluent (- no. 21)

I I I I I 1 I I I I I I I t I I I I 1400 lux) 1200 11M) lo00 900 800 700 600

Fig. A3. Spectra from high-flow trapping, nos. 21-24 (elapsed time from 2.67 to 2.92 h).

29

15-

Wavenumber (cm-l)


Fig. A.4. Spectra from high-flow trapping, nos. 25-30 (elapsed time from 2.97 to 3.3 h).

30

s-

- P) 0 c cd 7- e 2 - 4 s

5-

-

3-

-

1-

-1-

-3-

1500

no. 27: 3.13 h, molecular sieve effluent



no. 3 0 3.30 h, molecular sieve emuent

1 L A

I , I I , I I I I 1 I I I I , I I 1400 1300 1200 l1W 1oM) ow 8M) 700 6m

24

n:

16

12

a

4

0 1

no. 3 1: 3.37 h, molecular sieve effluent


-

no. 33: 3.50 h, molecular sieve effluent - no. 34: 3.57 h, molecular sieve effluent

/

no. 3 5 3.62 h, molecular sieve effluent

\ (stopped ClF3. increased to 500 sccm He)

h no. 36: 3.65 h, molecuIar sieve effluent

no. 37: 3.68 h, molecular sieve effluent h no. 38: 3.75 h, molecular sieve effluent


I 1400 1300 1200 1100 1WO 900 600 700 6w I I I I I 1 I I I I 1 I I I I I 1 I

Wavenumber (crn-l)

Fig. AS. Spectra from high-flow trapping, nos. 31-39 (elapsed time from 337 to 3.78 h).

31

7

6

5

4

3

2.

I.

0 1:

no. 1: 0.00 h, alumina effluent, started ClF3 flow


no. 3: 0.12 h, alumina effluent . . . .. . -


no. 5: 0.28 h, alumina effluent -*- --- ~



no. 8: 0.53 h, molecular sieve effluent .rrrrwly


no. 10 0.65 h, molecular sieve effluent

no. 11: 0.70 h, molecular sieve effluent - I I I I I I I I I I I I I 1 I 1 I I

I I400 1300 l2W 1100 loo0 900 8M) 700 boo

Fig. A.6. Spectra from low-flow trapping, nos. 1-11 (elapsed time from 0 to 0.7 h).

32

a 1

no. 12: 0.73 h, alumina effluent (- no. 11) A




no. 16: 1.03 h, molecular sieve effluent (- no. 11)




no. 20. 1.45 h, molecular sieve effluent (- no. 19) I 1 I I 1 I I 1 1 1 1 1 1 1 1 1 1 1

1400 lJ00 1200 1100 lo#) 9w 800 100 600

Fig. A.7. Spectra from low-flow trapping, nos. 12-20 (elapsed time from 0.73 to 1.45 h).

33

3.

15


L

no. 2 2 1.55 h, alumina effluent (- no. 20) A I h

no, 23: 1.60 h, alumina effluent (- no. 20)


A t no. 25: 1.68 h, alumina effluent (- no. 20)

no. 2 6 1.73 h, alumina effluent (- no. 20)

no. 27: 1.82 h, molecular sieve effluent (- no. 20) - no. 28 1.87 h, molecular sieve effluent

no. 29: 1.90 h, molecular sieve effluent e

no. 3 0 2.00 h, molecular sieve effluent I I I I 1 I I I 1 I 1 I I 1 I I I I

1400 1300 12M llca IWO so0 800 700 600

Wavenumber (cm-l)


34

1:

1(

8

6

4

2

0 1:



no. 33: 2.15 h, molecular sieve effluent I-c.


no. 35: 2.32 h, molecular sieve effluent c1






I I I I I I 1 I I I I 1 I I I I I I I 1400 1300 12W 1100 loo0 900 800 7M 600

Wavenumber (cm-l)


35

- no. 41: 2.97 h, molecular sieve effluent (- no. 38)

'1 4 no. 4 2 3.02 h, molecular sieve effluent

no. 43: 3.08 h, molecular sieve effluent 8

1 no. 44: 3.27 h, molecular sieve effluent, (stopped cE3, maintained 95 sccm He)

6-

no. 45: 3.48 h, molecular sieve effluent LIV

4- no. 4 6 3.63 h, molecular sieve effluent

I no. 47: 3.80 h, molecular sieve effluent

I no. 48: 4.17 h, molecular sieve effluent

no. 4 9 4.55 h, molecular sieve effluent 0 u1I

1500 1400 1300 1200 1100 loo0 900 800 700 600 I I I I I I I I I I I I 1 I I I I I

Wavenumber (cm-l)


36

Appendix B

EXTINCTION COEFFICIENTS USED IN THIS STUDY

The general approach for estimating halogen oxide concentrations from the FIlR absorbance bands was to draw upon the most consistent set of extinction coefficients available in the literature. Relying on this type of estimation is not the most accurate method, and it is clear that the use of calibration gases would give more precise answers. However, the limitations of this work and the inherent instability of many of the halogen oxides argue for the more pragmatic approach adopted in this study. In Table B. 1, all extinction coefficients, e (absorbance = concentration [torr] path [cm] e ) are based upon the maximum peak height of a particular feature, and the "recommended" values were used to report concentrations in this study. In situations where more than one infrared feature was available for prediction, the feature with the least interference was used (generally 1109 cm-1 for C Q , 1272 cm-1 for C102F, and 1317 cm-1 for CQF). Except for C102, the extinction coefficients from various sources in the table show reasonable agreement. The inherent instability of ClO, and the potential for CIOzF interference (in some studies) are the likely sources of this lack of consensus in the literature. The 854 reciprocal extinction value for C10, in Table B. 1 is almost certainly in error (too weak a line predicted) and is not in concert with the extinction values for the other asymmetric C1-0 stretches of the halogen oxides. We have adopted a value of 300 torr-cm per absorbance unit for the reciprocal extinction of the 1109-cm-1 line of ClO, as a conservative upper limit. It should be noted that a detailed and reliable high-resolution FTIR study of C102 has recently been conducted, but these results are not readily translated to low-resolution applications [Ortigoso, J., et al., J. Mol. Spectros. 156,89-97 (1992)l. In this study the weaker infrared features of C10, located at 944 and 2041 cm-1 were documented, and integrated intensities of the high-resolution features of the primary absorption bands were reported.

Table B.l. Summary of relevant extinction coefficients Recommended

Reciprocal reciprocal extinction coeff. Relative line Relative line extinction coeff.

Wavenumber (torr-cm per intensity, % intensity, % (torr-cm per Gas (cm-1) Referencesa absorbance) (literature) (this study) absorbance)

C103F 716 E. A.Smith [l] 66.4 30.1 65 45 A. Engelbrecht [2] 57.7 49.6 K-25 [3] 45.0 76.0

A. Engelbrecht [2] 115 24.9 1062 E. A.Smith [ 13 115 17.4 27 115

1317 E. A.Smith [l] 20.0 100 100 34.2 A. Engelbrecht [2] 28.6 100 K-25 [3] 34.2 100

I

C102F 1106 E. A.Smith [l] 123 A. 3. Arvia [4] 238

0 K-25 [3] 240 P

35.6 55 240 40.6 36.5

1272 E. A.Smith [l] A. J. Arvia [4] K-25 [3]

43.8 100 100 87.6 96.8 100 87.6 100

ClO, 1109 E. A.Smith [ 13 854 A. H. Nielsen [5] 185

300

ClF, 760 K-25 [3] 468 468

HF 4039 K-25 [3] 558 - 558 uReferences: [l] Smith, E. A., et al., Infrared Spectra of CIO;!, C102F and CIOjF, GAT-T-687, Goodyear Atomic Cop., Portsmouth, Ohio

(October 1959); [2] Engelbrecht, A,, et at., J. Inorg. Nucl. Chem. 2,348 (1956); [3] K-25 local reference from Schwab and Farrar, updated by L. D. Trowbridge; [4] Arvia, A. J., et al., Spectrochim. Acta 19, 1449 (1963); [5] Nielsen, A. H. et al., J. Chem. Phys. 20,1878 (1952).

.

ORNLPTM-13403

INTERNAL DISTRIBUTION

1. RRAigner 2. J. F. Alexander 3. D. P. Armstrong 4. C. E. Bamberger 5. W. D. Brickeen 6. M. E. Buchanan 7. S.N.Burman 8. W.A.Camp 9. R.A.Campell

10-13. S. G. Coffey 14. A.G.Croff 15. S. Dai 16. G. D. Del Cul 17. J. R. DeVore 18. J. R. DiStefano 19. R. L. Faulkner 20. U. Gat 21. L. L. Gilpin 22. Q. G. Grindstaff 23. N. R. Smyrl 24. J. S. hey 25. P. S . Johnson 26. R. T. Jubin 27. J. R. Keiser 28. R.A.Kite .

29. S.L.Loghry 30. R. S. McKeehan 31. L. E. McNeese 32. T. C. Morelock 33. T.W.Morris 34. S.H.Park 35. B. D. Patton 36. F. J. Peretz 37. D. W. Ramey 38. J. C. Rudolph

39-42. J. E. Rushton 43. D. W. Simmons 44. N. R. Smyrl 45. R. M. Szozda

5 1. L. D. Trowbridge 52. K. L. Walker 53. J. P. Young

54-58. D. E Williams 59. ER Document Management

Center 60. Central Research Library 61. O W Laboratory Records -

62-63. ORNL Laboratory Records

46-50. L.M.Toth

for OSTI

EXTERNAL DISTRIBUTION

64. J. H. DeVan, 107 Orange Lane, Oak Ridge, TN 37830 65. J. R. Engel, 118 E. Morningside Drive, Oak Ridge, TN 37830 66. G. R. Hudson, Project Management Division, Department of Energy, Oak

Ridge Operations, P.O. Box 2001, Oak Ridge, TN 37831 67. R. L. Jones, Paducah Gaseous Diffusion Plant, Bldg. C300, P.O. Box 1410,

Paducah , KY 42002-1410 68. M. R. Jugan, Environmental Restoration, Department of Energy, Oak Ridge

Operations, P.O. Box 2001, Oak Ridge, TN 37831 69. J. J. Laidler, Director, Chemical Technology Division, Argonne National

Laboratory, 9700 S. Cass Avenue - Bldg. 205, Argonne, IL 60439 70. N. W. Lingle, Environmental Restoration, Department of Energy, Oak Ridge

Operations, P.O. Box 2001, Oak Ridge, TN 37831 71. D. W. Neiswander, 9317 Norlake Circle, Knoxville, TN 37922 72. K. J. NOW, Henley Point-River Road, Kingston, TN 37763

RC

73. A. L. Olson, Idaho National Engineering Laboratory, P.O. Box 1625, MS-5219,

74. L. P. Pugh, 2024 Cedar Lane, Kingston, TN 37763 75. R. G. Russell, Paducah Gaseous Diffusion Plant, Bldg. C710, P.O. Box 1410,

76. A. J. Saraceno, Portsmouth Gaseous Diffusion Plant, Bldg. X710, P.O. Box 628,

77. J. E. Shoemaker Jr., Portsmouth Gaseous Diffusion Plant, Bldg. X100, P.O. Box

78. R. E. Thoma, 119 Underwood Road, Oak Ridge, TN 37830 79. P. G. Wooldridge, Paducah Gaseous Diffusion Plant, Bldg. C7 10, P.O. Box

80. R. G. Wymer, 188-A Outer Drive, Oak Ridge, TN 37830 81. E. L. Youngblood, 198 N. Purdue Avenue, Oak Ridge, TN 37830

Idaho Falls, ID 83415-5219 I

Paducah, KY 42002-1410

MS-2212, Portsmouth, OH 45661-2212

628, MS-1223, Portsmouth, OH 45661-1223

1410, Paducah , KY 42002-1410

Documents

Laboratory Tests Using Chlorine Trifluoride in Support of .../67531/metadc...regarding the use of chlorine trifluoride (ClF3) for removal of uranium-bearing deposits in the Molten